1. Field
Although not so limited in its utility or scope, implementations of the present invention are particularly well suited for incorporation in material sortation systems such as those used in moving mail pieces through various stages of processing in a mail processing facility, for example.
2. Brief Description of an Illustrative Environment and Related Art
Material handling operations frequently involve the use of transport systems including networks of conveyor belts and roller conveyors. In a typical material sorting environment, a material receptacle is located at each terminus of a selected plurality of termini for the collection of material exiting the sortation system. Commonly, an output chute corresponds to a terminus and includes a surface sloped downwardly toward the receptacle for guiding material exiting the sortation system into the receptacle situated below the chute. Illustrative, commonly used, material receptacles include flexible receptacles such as sacks and bags, for example, and rigid receptacles such as boxes, crates, cartons, and carts, for instance.
In a typical package or mail sortation system, multiple, adjacent output chutes are arranged along a base structure such as a longitudinally extending main framework adapted for supporting plural chutes. Moreover, the exit (or drop-off) ends of adjacent chutes, each of which chutes typically extends along an axis orthogonal to the longitudinal axis of the main framework, are generally coextensive with respect to the main framework from which they depend. There are occasions on which it is desirable to transport material exiting a chute to a location farther away from the main framework than that material would be transported if it were simply allowed to fall off the drop-off end of the chute. That is, it is sometimes desirable to effectively extend the discharge point of an output chute. The desirability of such circumstances may depend, for instance, on the type of material receptacle being used to contain packages exiting the chute in question and the types of receptacles being used to contain packages exiting neighboring chutes. Various types of extensions are used for such purposes including, for example, slide extensions, roller extensions, and conveyor-belt extensions.
Presently, the roller conveyor extensions in wide use are modules which, when not in use, are detached from the main framework from which they depend when in use. Typically, these roller conveyor extension modules are heavy and cumbersome apparatus frequently requiring more than one person to detach and relocate them for storage. In addition to the demand in time and worker effort to detach and attach roller conveyor extension modules, roller extension modules must be stored in a safe place, out of the way of material-handling operations and walkways, for example, which consumes often limited working space.
Accordingly, there is a need for a roller extension that need not be removed for storage and which, in a typical embodiment, is conveniently movable between storage and operative positions by a single person.
In various embodiments, a self-storing roller conveyor extension includes a base frame adapted for one of permanent and removable dependence from the main framework supporting a material-guiding output chute. The base frame of a typical embodiment includes first and second laterally spaced, parallel elongated tracks extending along a first axis, each track having a rearward end and forward end. Adapted for translational reciprocation along and between the rearward and forward ends of the first and second tracks, respectively, are a first carriage and a second carriage. The carriages are pivotably attached to a roller support structure as described in further detail below.
A roller support structure includes first and second laterally spaced, elongated frame members arranged in parallel and extending along a second axis. Each of the first and second frame members has a first end and a second end coinciding with, respectively, back and front ends of the roller support structure. A plurality of rollers is supported by, and extends between, the parallel frame members of the support structure. Each of the rollers rotates about an axis perpendicular to the second axis and parallel to the axes about which other rollers among the plurality of rollers rotates. The first and second elongated frame members of the roller support structure are pivotably attached to, respectively, the first and second carriages in a location less distant from the back end of the roller support structure than the front end of the roller support structure. The pivotable attachment of the roller support structure to the carriages renders the roller support structure capable of both rotational motion about a pivot axis and rearward and forward reciprocal motion with respect to the base frame.
In a typical implementation, when the base frame is oriented such that the tracks extend parallel to a first plane that is disposed one of (i) parallel to and (ii) at an angle of less than 45xc2x0 with respect to a horizontal plane, the roller support structure is pivotable about a pivot axis perpendicular to the first axis between a first, storage position and a second, operative position as follows. The storage position is such that the first and second elongated frame members of the roller support structure extend downwardly below the base frame along a second plane that is disposed one of (i) parallel to and (ii) at an angle greater than 0xc2x0, but less than 45xc2x0 with respect to a vertical plane. The operative position is typically such that the first and second elongated frame members one of (i) extend horizontally and (ii) decline away from the pivot axis at an angle greater than 0xc2x0, but less than 45xc2x0 with respect to a horizontal plane that includes the pivot axis.
In various embodiments, at least one of (i) the base frame and (ii) the roller support structure includes at least one horizontally extending protrusion and the other of the base frame and the roller support structure includes a protrusion-engaging surface with which the horizontally extending protrusion can be selectively placed in supporting engagement to retain the roller support structure in an operative position. In one illustrative version, the first and second elongated frame members of the roller support structure are pivotably mounted to respective carriages such that the elongated frame members are to the exterior of the tracks. In one such version, a horizontally extending protrusion depending from the roller support structure extends inwardly for selective supporting engagement with a protrusion-engaging surface depending from the base frame, while, in another such version, a horizontally extending protrusion depending from the base frame extends outwardly for selective supporting engagement with a protrusion-engaging surface depending from the roller support structure. In various versions including a horizontally extending protrusion, the applicable one of the base frame and the roller support structure includes at least two protrusion-engaging surfaces disposed at different heights with respect to a horizontal plane such that the roller support structure can be alternatively supported at different angles with respect to a horizontal plane by the alternate supporting engagement of the horizontally extending protrusion with each of the at least two protrusion-engaging surfaces.
In a typical illustrative setting, a roller conveyor extension is mounted for dependence from a framework such that the base frame of the conveyor extension is underneath the downwardly sloped surface of a material guiding chute. When the roller support structure is in a storage position, it extends downwardly below the material guiding chute in location rearward of the drop-off end of the chute. In order to deploy the roller support structure of the roller conveyor extension, a user reaches below the chute, draws the roller support structure linearly toward him/herself such that the carriages move toward their forwardmost positions, pivots the roller support structure to raise the extension drop off end (i.e., front end) of the roller support structure, and places at least one horizontally extending protrusion in supporting engagement with a protrusion-engaging surface to maintain the roller extension in a deployed position in which the extension drop off end is more forward than (i.e., extends beyond) the drop off end of the chute to which the roller conveyor extension corresponds.
In additional embodiments, a carriage pull depends from, and extends forwardly of, at least one of the carriages. Each carriage pull is adapted for grasping by a user for movement of the roller support structure forward and backward on the tracks. The carriage pull is particularly useful for accessing a stored roller support structure when the carriages are near their rearwardmost positions on the tracks.
In further alternative embodiments, a base frame includes an elongated track extending parallel to a first axis and having a rearward end and a forward end. A roller support structure having back and front ends includes an elongated frame member extending along a second axis and having first and second ends coinciding with back and front ends of the roller support structure. A plurality of rollers is supported by and along the length of the frame member. Each roller is supported for rotation about an axis extending along an axis perpendicular to the second axis. A carriage adapted for translating reciprocation between the rearward and forward ends of the track is pivotably attached to the roller support structure in a location less distant from the back end of the roller support structure than the front end of the roller support structure such that the support structure is capable of both rotational motion about a pivot axis and rearward and forward reciprocating motion with respect to the base frame.